Drought and water restrictions make water conservation a top priority this season, said Roch Gaussoin, turfgrass specialist in NU's Institute of Agriculture and Natural Resources. Wise watering also is good for lawns.
"Many homeowners are notorious for applying too much water to their lawns," he said. "Water restrictions in 2002 actually resulted in better lawns because homeowners were not overwatering."
A drought year isn't time to think about keeping a lush, green lawn, he said. This spring and summer, lawns will require new management practices.
During spring, the goal should be to increase grass root development. This is important every spring, but it's essential during drought, he said. Strong roots that reach deeper into soil allow grass to better withstand hot weather and water stress.
Homeowners should avoid excessive nitrogen fertilization and consider core aerification, or plugging, to promote root growth and increase water infiltration, he said.
"Consider reducing your fertility applications this spring if drought and potential restrictions appear to be unavoidable," he said. "Rather than two (fertilizer) applications consider applying only one, possibly with a crabgrass preventor or pre-emergent herbicide."
The herbicide/fertilizer combination should be applied no earlier than April 15 and no later than the first week in May for optimal weed control.
Gaussoin recommends not mowing too low this spring. Instead of lowering the mowing height, set it at about 2.5 to 3 inches for Kentucky bluegrass and 3 to 4 inches for tall fescue. Using a higher mowing height will result in deeper roots.
"Do not remove grass clippings," he said. "Clippings are a great nutrient source and the organic matter addition helps conserve moisture."
This may not be the year to restore lawns thinned and damaged by previous years of drought, Gaussoin said. Previously, many municipalities that enacted water restrictions made allowances for establishing new lawns, but that may not be true this year, he said. Homeowners should check with local authorities about voluntary or mandatory guidelines for lawn establishment before seeding or sodding.
On established lawns this spring, "irrigate deeply and infrequently," he said. "About an inch per week in a single irrigation will do. Do not put more water on than the soil can take. Runoff, especially during drought, is unacceptable."
During summer months, irrigation can be decreased and frequency increased. About a half-inch every two to three days for a total of 1.5 inches per week will do. If it rains, subtract the amount from weekly waterings.
"If water restrictions mandate a change in irrigation practices follow the directions of your municipality," Gaussoin said. "Turfgrass is much more resilient than people realize."
Gaussoin said research in Colorado during summer 2002's prolonged drought showed that Kentucky bluegrass stays green during the summer with about a half-inch of water per week in a single irrigation. The soil type was clay loam.
Alternatively, when Kentucky bluegrass is not irrigated it will turn brown and go dormant. While dormant, it can conservatively go three to four weeks without water as long as foot or vehicle traffic is minimized. If it doesn't rain during that time, consider a light half-inch irrigation to insure lawn survival until late summer/early fall rains occur.
urf-type tall fescue tolerates drought by maintaining growth as long as water in the soil is recharged, Gaussoin said. If the soil water is totally depleted, tall fescue will require supplemental irrigation to insure survival.
The work in Colorado showed that, under extreme drought conditions, tall fescue requires approximately an inch of water per week to survive.
"If spring rains are low and we start the growing season with deficient soil moisture, followed by the anticipated below normal rainfall summer, tall fescue will require irrigation for survival," Gaussoin said.
Roch Gaussoin, Ph.D., professor, agronomy and horticulture, (402)472-8619
Sandi S. Alswager, IANR News and Publishing, (402)472-3030
